Question 1073673
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Use the formula

{{{a^2 - b^2}}} = (a+b)*(a-b).

Apply it with a = s+2, b = s.  You will get

{{{(s+2)^2 - s^2}}} = {{{(s+2+s)*(s+2-s)}}} = 2*(2s+2) = 4*(s+1).
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